1866.] Dr. Davy on the Bursa Fabricii. 95 



spermatozoa have been sought for, a drop of a solution of common salt of 

 the sp. gr. 1038, has been added to the fluid to be examined. 



In the descriptive part which follows, I propose to confine myself to the 

 more striking examples illustrative of the peculiarities adverted to and likely 

 to aid in accounting for them, passing over the several species, or very briefly 

 noticing them, when displaying no marked difference. 



I. Common Fowl (Gallus domesticus).— I begin with this bird, as I have 

 had the best opportunity of examining it at different ages. 



1. Of a chicken four days old, the bursa was about the size of a small 

 pea ; it communicated with the cloaca, and was em^ty. 



2. Of another chicken, seventeen days old, found dead on the 10th 

 of March from cold, the bursa measured "3 by "2 inch; it was distinctly 

 plicated internally ; it was empty. 



3. Of a young cock, eleven weeks old, examined on the 16th of June, 

 the bursa, of a globular form, was 1 • 1 inch in diameter ; it communicated 

 with the cloaca by a narrow neck about '15 inch in width; internally it 

 was strongly plicated ; the projecting laminae were of a crescentic form, 

 about twenty in number, and their width, where widest, was about '4 inch. 

 It contained some turbid fluid, in which were numerous mucus-like cor- 

 puscles and a few well-defined spermatozoa. The testes were large ; besides 

 sperm-cells, they contained some spermatozoa. 



4. Of another cock, hatched in July, examined when nineteen weeks 

 and six days old, the bursa, 1"2 inch in diameter, weighed 74 grs. ; it 

 was similar to the preceding in structure, and was empty. 



5. Of a third male, hatched on the 19th of September, examined when 

 twenty-one weeks and one day old, weighing six pounds, the bursa was 1*5 

 inch in diameter ; its plicse like the preceding, its opening into the cloaca 

 large ; many spermatozoa were found in the little turbid fluid with which 

 they were moistened. The testes were large; the left weighed 144 grs., 

 the right 130 grs. ; the vasa deferentia were small. 



6. Of a fourth, hatched on the 18th of October, examined on the 20th 

 of March, when seventeen v*'eeks and seven days old, weight five pounds, 

 the bursa, compared with the preceding, was of diminished size ; its dia- 

 meter only -6 inch, its plicae few, short and thick, and bloodshot; its 

 opening into the cloaca large and exposed, without any valvular protection. 

 It contained a little thick mucus, in which there was commingled an ap- 

 pearance of spermatozoa. The testes were large, and abounded in sperm- 

 cells and spermatozoa ; and the vasa deferentia were well developed, and 

 contained a cream-like fluid rich in delicate spermatozoa*. 



* The examination was made whilst the fowl was still warm. The fluid of the testes 

 had a distinct alkaUne reaction. In other instances I have obtained the same result, 

 showing thus a marked difference when compared with the ovum, the yelk of which, 

 when fresh, I have always found to exhibit an acid reaction, proper precautions being 

 taken to avoid contact with the alkahne white. See the author's * Physiological Re- 

 searches ' (1863), p. 426. 



